In the technology of pressure measurement, absolute and relative pressure sensors are among the sensors which are used. In the case of absolute pressure sensors, a pressure to be measured is registered absolutely, i.e. as a pressure difference relative to a vacuum. With a relative pressure sensor, a pressure to be measured is recorded in the form of a pressure difference relative to a reference pressure. The reference pressure is an ambient pressure existing where the sensor is located. In most applications, this is the atmospheric pressure at the site where the sensor is being used.
Pressure measuring devices are applied in a multitude of industrial branches, e.g. in chemistry and in the foods industry. In these industries, one frequently finds large plants, in which pressures are to be measured at pluralities of locations for following, controlling, regulating and/or automating processes running in the plants. For this, a multitude of pressure sensors can be used, for instance sensors for various measurement ranges.
Pressure measuring devices are frequently exposed to moisture. This is e.g. the case, when they are used in locations with lasting high air humidity, e.g. in the tropics, when, in the foods industry, containers are cleaned with hot water and subsequently rinsed with cold water, or when the pressure of a cold medium is to be measured and condensate forms because of a higher surrounding temperature.
Pressure sensors usually have a measuring cell and sensor electronics connected with the measuring cell. The measuring cell includes an electromechanical transducer, which converts a reaction of a pressure sensitive element into an electrical signal, which is brought into the sensor electronics where it is available for further evaluation and/or processing. The sensor electronics must, consequently, be accessible for a connection of the same e.g. to an instrument electronics or a supply and/or signal evaluation unit. Exactly the sensor electronics and its electrical connections are, however, especially sensitive to moisture and mechanical loads.